Ecchiloid

Ecchiloid a combination of the terminology Ecchi and Vocaloid, pertains to Fanmade Vocaloids created with the trait of being very sexual, dirty-minded or perverted. Ecchi being a slang term used in the Japanese language to refer to Japanese media having sexual overtones.

Depiction
Ecchi vocaloid tend to be portrayed as very sexually aggressive, perverted/dirty-minded. Usually willing to be sexually open in public or around friends, Ecchiloid characters are known to be mostly extroverted in nature due to this but that isn't to say an Ecchiloid can't be portrayed as polite and elegant in public but in the privacy of their own home or rooms they turn into a sexual deviant.

History
Not much is known when Ecchiloid first started appearing but it might have been around the time when Voiceroid ACME, Iku was released with the idea of being a perverted maid. However, ecchiloid or not there have been depictions of vocaloid characters being drawn/singing in a sexual or perverted manner.

Ecchiloid on Fanloid Wiki

 * Aieki, Iku is a fanmade derivative based off ACME, Iku

Trivia

 * ACME, Iku can be known as the first Vocaloid in the series to start the Ecchiloid craze